1. Field of the Invention
The present invention relates to a power supply device including a plurality of stacked secondary batteries for example.
2. Description of the Related Art
A secondary battery is not only used for replacement of a primary battery but also widely used as a power supply of electronic devices such as mobile phones and IT devices. Especially, due to high-energy density, a non-aqueous electrolyte secondary battery represented by a lithium ion battery is increasingly applied to electric automobiles and industrial large-scale electric devices. Therefore, conventionally, in order to obtain higher voltage, a collective battery in which a plurality of non-aqueous electrolyte secondary batteries is stacked so as to form one power supply is proposed (for example, refer to JP-A-2002-134078).
However, a configuration of the collective battery according to the above conventional technique includes the following problem.
FIG. 9 is an exploded perspective view used to explain a problem of the collective battery formed by a plurality of batteries according to the conventional technique. As shown in FIG. 9, a collective battery 100 includes an assembled battery 110, an open box shape container 120 having an opening 121, and a lid 130.
The assembled battery 110 is a stack in which a plurality of batteries 111 having a hexahedral outer shape is arranged in such a manner that front surfaces and back surfaces face each other. In the batteries 111, electrodes 112 having different polarities from each other are connected by a bus bar 113. Thereby, the batteries 111 are connected in series so as to form a high-voltage assembled battery as a whole.
The assembled battery 110 is accommodated in the container 120, and the opening 121 of the container 120 is sealed by the lid 130. An electrode terminal 112a serving as a positive electrode and an electrode terminal 112b serving as a negative electrode for the entire assembled battery 110 are respectively electrically connected to a positive electrode terminal 131a and a negative electrode terminal 131b provided on an upper surface 130a of the lid 130. Thereby, the power of the assembled battery 110 is taken out as the power of the collective battery 100.
An electric current discharged by the assembled battery 110 is as large as tens to hundreds of amperes especially for use of a large electric load such as electric automobiles. Therefore, for connecting the positive and negative electrode terminals 112a and 112b of the assembled battery 100 and the positive electrode terminal 131a and the negative electrode terminal 131b of the lid 130, a metal bus bar having strong power durability and high rigidity or the like is mainly used as a connection member in place of a flexible cable such as a stranded wire.
However, a working space for attachment of the connection member is a narrow space where the lid 130 and upper surfaces 111a of the batteries 111 face each other. Further, in a case where lithium ion secondary batteries are used as the batteries 111, there is a need for a control circuit for performing active control at the time of charge-discharge, and the control circuit is provided on a main surface 130a or a back surface of the lid 130 as described in JP-A-2002-134078. Thus, particularly in a case where the control circuit is provided on the back surface of the lid 130, the working space described above is furthermore narrowed down.
Therefore, for connecting the electrode terminals on the side of the assembled battery 110 and attachment terminals (not shown) of the lid 130 exposed on the back surface of the lid 130 in the collective battery 100, delicate and careful operations are required for each of steps of positioning, temporary fixing, and final fixing, so that productivity is lowered.
As described above, in a power supply device as in the collective battery according to the conventional technique, a structure around the electrode terminals is made in a cumulated fashion, and there is a problem that the productivity is lowered.